This invention relates to automobile convertible tops and, more particularly, to a hydraulic operator for a convertible top having a movable rear bow.
Many convertible tops designed for high-end sports or other two-seat vehicles employ a movable rear or 5-bow. With the top lowered, the tonneau is opened to enable raising the top. The rear bow is then raised to enable closing of the tonneau. The rear bow is then lowered and secured to the tonneau to close the passenger compartment. To lower the top, the rear bow is raised to enable opening of the tonneau. The top is then lowered, after which the tonneau is closed. This system eliminates the need for a separate boot cover and presents a more aesthetically pleasing vehicle in both the top raised and lowered positions.
Power tops that utilize a movable rear bow normally provide a pair of cylinders to operate the top, and require manual operation to raise and lower the rear bow or provide an additional pair of cylinders to operate the rear bow. These top operating systems are unduly complex and require use of complex valving to accomplish the correct sequence of top and bow movements to raise and lower the top.
Developments have led to a hydraulic control system in which a single pair of cylinders can be used to sequentially operate both the top and rear bow movements operating through a mechanical linkage. Such a system is disclosed in U.S. Pat. No. 5,620,226xe2x80x94Sautter, the entire disclosure of which is incorporated herein by reference.
There is a need for a convertible top operating mechanism which uses a simplified hydraulic control system to sequentially operate the top and tonneau movements to raise and lower the top.
It is therefore an object of this invention to provide a for a convertible top operating mechanism which uses a simplified hydraulic control system to sequentially operate the top and bow movements to raise and lower the top.
In general, this invention comprises a hydraulic control system for operating cylinders that control movement of a hydraulic top and cylinders that control movement of a tonneau.
In one aspect this invention features a convertible top operating mechanism which includes a bi-directional hydraulic pump which is selectively connected to top-operating hydraulic cylinders and tonneau-operating hydraulic cylinders by a two-way, 2-condition control valve to selectively raise and lower the top and tonneau.
In one embodiment, a mechanical linkage connects the top-operating cylinders with the movable rear bow and is operable to sequentially move the rear bow in a manner that accommodates tonneau operation in coordination with top operation.
In a first valve position, both ends of the top cylinders are connected to both sides of the pump, while one end of the tonneau cylinders are connected to one side of the pump, and the other tonneau cylinder ends are blocked. When the pump is inoperative (condition 1), this allows the top to float, but secures the tonneau against movement.
In this first valve position, operation of the pump in one direction will extend the top cylinders only (condition 2) to raise the top; it will pressurize one side of the tonneau cylinders, but they cannot move since the exhaust side is blocked. Pump operation in the other direction will retract the top cylinders only (condition 3) to lower the top; the tonneau cylinders are connected to exhaust, but cannot move since the pressure side is blocked.
In a second valve position, both ends of the tonneau cylinders are connected to both sides of the pump, while one end of the top cylinders are connected to one side of the pump and the other top cylinder ends are blocked. If this position were used when the pump is inoperative, the tonneau would be unpressured and float, while the top would be secured against movement; however this condition is not desired and, consequently not utilized.
In this second valve position, pump operation in one direction will extend the tonneau cylinders only (condition 4) to raise the tonneau. Operation of the pump in the other direction will retract the tonneau cylinders only (condition 5) to lower the tonneau. In both conditions 4 and 5, the blockage of one end of the top cylinders prevents their movement.